Automatic turbine control system



June 2, 1942. I JOHNTZ ETAL 2,285,208

AUTOMATIC TURBINE CONTROL SYSTEM Filed April 10, 1940 5 Sheets-Shea l o ms AT L OPENS mopav AT 400 RPM 4FU5LL OPEN VALVE L CLOSED AT FULL SPEED AT FULL CLOSED VALVE FROM TURBINE SHAFT inventors 1 Tracy E. \Johntz, Claude W. P! ce,

Their- Attorney.

June 2, 1942. "r. E. JOHNTZ ETAL AUTOMATIC TURBINE CONTROL SYSTEM Filed April 10, 1940 5 Sheets-Sheet 2 OFF lhvenbors I Trac B. Johnbz,

Clau e W. Place,

y g Their Attorney June 2, 1942.

T. E. JOHNTZ ET AL AUTOMATIC TURBINE CONTROL SYSTEM Filed April 10, 1940 5 Sheets-Sheet 3 w Z n 3; r wt w bJ t WWB m w m x TIC J1me 9 T. E. JOHNTZ ET AL AUTOMATIC TURBINE CONTROL SYSTEM Filed April 10, 1.340 5 Sheefia-Sheet 4 Inventor's: Tracy EuJOhT'ItZ,

W P C8 by Attorney.

Cla de Theii June 9 T. E. JOHNTZ ETAL AUTOMATIC TURBINE CONTROL SYSTEM 5 Sheets-Sheet 5 MATCHER Filed April 10, 1940 Cla deW Place,

Then- Attorney.

Inventors Tr" acg E3. Johnoz, b9 7 Patented June 2, 1942 AUTOMATIC TURBINE CONTROL SYSTEM Tracy E. Johntz Wilmette, and Claude W. Place, La Grange, 111., assignors to General Electric Company, a corporation of New York Application April 10, 1940, Serial No. 328,848

28 Claims.

This invention relates to prime mover-generator plants and more particularly to control systems therefor.

The starting and stopping of prime mover power plant units entails many operational steps which must be performed in a proper se quence, the continuity of the sequence steps being determined by the conditions pertaining to the completion of the last preceding step.

In the case of elastic fluid turbine power plants, the-starting and control of various pieces of apparatus auxiliary to the turbine must be ccordinated with the control of the turbine valves in a definite relation in order that the turbine will function properly and to avoid injury thereto. It is desirable to. provide such a power plant for automatic control whereby proper starting and stopping of the power plant unit in minimum time may be insured and also in order that the unit may be controlled by a supervisor lo cated at adesired distance therefrom. It is therefore an object of this invention to provide a reliable system for automatically controlling a power plant including a prime mover, a generator, and appurtenant auxiliary apparatus.

More specifically, it is an object of the invention to provide a new and improved system for controlling a prime mover power plant whereby the prime mover may be automatically started from standstill, through a plurality of steps of speed increase up ,to full normal running speed. A further object of this invention is to provide a new and improved system for starting a prime mover power plant including various auxiliary V apparatus the control of which is coordinated with the control of the main prime mover so that they are thrown into operation at the proper time during the starting sequence of the power plant, A more specific object is to provide the control system with means for automatically shutting down the power plant and the auxiliary apparatus, the various operational steps being performed in proper order so as to preclude injury to the primemover.

Still another object of the invention is to provide a system for automaticallystarting a prime mover power plant from standstill and bringing it up to full normal speed through a plurality obtaining with respect to the turbine or any of the auxiliaries and in certain emergencies, to

cause a shut down of the plant.

Still another object of the invention is to pro vide a new and improved control system for" automatically starting a prime mover dynamo plant in which the prime mover is brought up to a speed corresponding to the frequency of the line to which the generator is to be connected and the generator then automatically synchronized and connected to the line. A more specific object is the provision of means for connecting the dynamo of the power plant for independent load and'voltage control following the connection of the dynamo to the line.

In accordance with the illustrated embodiment of our invention we provide a control system for an elastic fluid turbine prime mover power plant including an electric generator adapted to be connected to station buses. Various motor driven auxiliary units associated with the power plant and other apparatus forming a part thereof, such as the various turbine valves, are controlled by the system during both starting and stopping operations in a predetermined sequence of steps, various interlocks and other checking devices being provided so that in the event of a failure of any particular piece of apparatus to operate properly, the progression of the starting cycle will be immediately arrested, or the power plant will be immediately shut down. In starting, thecont-inuity of the automatically controlled sequence of steps is disrupted at a number of points in order to give a floorman an opportunity to,check on the operation of the power plant apparatus. Means are provided so that the floorman, if everything is in proper order, may allow the continuation of the starting operation. After the prime mover power plant has been brought to full running speed, the frequency of the generator is matched with the line frequency and then synchronized and connected to the line. After such connection is effected, the control of the prime mover is transferred to the usual speed governor, while the control of the generator voltage and load is transferred to the station supervisor. Control of the prime mover is maintained at alltimes by various protective devices some of which, responsive to extreme, abnormal conditions, will effect the immediate shut down of the prime mover, while others responsive to pie-emergency,

' solenoid I8.

thereof from the line and thereafter the gradual shut down of the prime mover and various auxiliary apparatus in proper sequence.

For a consideration of what we believe to be novel and our invention, attention is directed to the following description and the claims appended thereto taken in connection with the accompanying drawings.

In the drawings Fig. 1 is a diagrammatic layout of a prime mover power plant'as adapted for automatic control; Fig. 2 is a developmental layout of the contact arrangement for the drum controller embodied in the control system; Figs. 3a, 3b, and 3c are a schematic wiring diagram for the I control system of the power plant and auxiliary apparatus; and Fig. 4 is a detail view of one part of the apparatus embodied in the control system.

In order to simplify the description of the control system as much as possible, diagrammatic symbols have been used wherever possible to represent ;well known elements, the nature and operation of which elements are well known by those skilled in the art. For further convenience in showing the electrical connections, simple solenoids are frequently shown for closing and holding closed, certain electrical connections, valves and the like, relying upon either a spring or gravity to cause the opening thereof or vice versa. It is'obvious, of course, that sound engineering maydemand theuse of means more positive in its action such as, for example, an electric motor. Such a motor would be connected to the device through suitable gearing and be energized'for driving the device to the operating position and then be automatically deenergized. To return the'device to the previous vexcess speed condition of the turbine.

tacts 28 upon the occurrence of a predetermined Upon the deenergization of solenoid I 8, the spring I1 will initiate the movement of the valve to the closed position. The emergency speed governor is arranged also to open other contacts 30 during emergency conditions.

A suitable dash pot means indicated at 29 may be provided for preventing the steam pressure which acts upon the unbalanced valve from slamming it too hard against the seat. The trigger of the emergency governor 20 may be reset by any suitable means or manually after a thorough inspection of equipment following'a tripping thereof.

The. throttle valve I5 is preferably of a type having a relatively wide range of adjustment particularly near the closing end of its stroke so that it is not unduly critical in the slightly opened positions when the unloaded turbine is gradually accelerated to normal running speed. Such valves are well known in the art and are indicated in the drawings by the long tapered disk. The throttle valve I5 is adjustable through various positions from fully closed to the fully opened condition for accelerating the 'turbine II] from standstill to full running speed The throttle I spring 24 being arranged between the lower surcondition, the motor would be energized for rotation in the opposite direction until automatically stopped upon the device reaching the predetermined condition. It is obvious'that any such minor changes may be made in the control scheme in order to incorporate desired principles of engineering design by any one skilled in the art. 7

Referring now to the drawings, in Fig. 1- is shown a typical power plant or power plant unit, comprising an elastic fluid turbine I0 coupled for driving an electric current generator II and an exciter I2. The turbine ID is adapted to be supplied with operating fluid through .the conduit I3, the flow of operating fluid being controlled by an emergency stop valve I4, a throttle valve I5, anda speed governor control valve IS; The stop valve I4 is normally biased to the .closed position by suitable means indicated by spring I1 and adapted to be actuated to the open position by a suitable. motor means represented by a. Interlock contacts I3 are arranged for actuation with the stem of the stop valve to close a circuit, indicating the opened condition of the stop valve, for reasons as will be explained in connection with the control system. While the motor operator I8 is shown in this instance as comprising a simple solenoid device, it is obvious that any well known suitable motor is represented thereby. This stop valve during normal turbine operation is in the opened position and is adapted to be released for closing upon the occurrence of anypredetermined abnormal condition of operation of the power plant system. The turbine shaft may be provided with a suitable emergency speed governor, indicated at 20, which may be adapted for breaking the circuit of the solenoid I8 by opening conface of the piston and the lower end of the motor cylinder for biasing the valve to the closed position. Operating fluid is admitted to the servomotor 23 through port connections 25 and 26 and a suitable pilot valve 21. apart valve heads is arranged upon the stem 32 of the valve 21 and controls the flow of fluid to and from the hydraulic motor 23 in a well known manner. The'pilot valve is adapted for adjustment by a suitable reversible electric pilot motor 33 which is coupled by gearing 34 and screw threaded Spindle 35 with one end of the floating lever 36. Lever 36 is connected at an intermediate point with the valve stem '32 of the pilot valve andat the opposite end with the stem of the hydraulic motor for returning the pilot valve to the normal position after movement by pilot which condition will admit operating fluid from the supply conduit to the turbine I0 sufllciently for warming it to operating temperature without rolling it. The limit switch 42 is normally open but is adapted to close when the switch 4| opens. The limit switch 43 is normally closed but opens at a point corresponding to a partially opened position or the throttle valve which is the condition for admitting operating fluid to the turbine for drivlng it at a no-load speed of, for example, 400 R. P. M, The limit switch 44 is normally open'and closes onlyat the fully opened position of the throttle valve. The limit switch 45 is normally closed and opens only at the fully opened position of the throttle valve. The limit switch 46 is normally closed A pair of spaced and opens only at the fully closed position of the throttle valve.

Means are provided for tripping the throttle valve to the closed position at any time independent of the condition of the operating motor 33 and the pilot valve 21. A trip valve is provided having a pair of spaced apart heads arranged upon an operating stem 52. The trip valve is connected by pipes 59 and 54 with the connections 25 and 26in such a manner that when the valve is tripped, fluid may flow from the motor cylinder above piston 22 through pipes 53 and, 54 into the motor cylinder below piston 22, the closing of the throttle valve being efiected by the spring 24. The trip valve stem is biased in the upward or-tripping direction by a spring 55 arranged between the lower head and the end wall of the trip valve casing. The trip valve is adapted to be restrained in the position shown by means of a suitably arranged pivoted latch 59 engaging the upper end of the valve stem 52. The latch 59 is normally biased to the engaging position by a spring GI and is actuable to the valve releasing position by means of a solenoid 62. A number of position switches 63, 64 and G5 are provided on the valve stem 52 for controlling various electrical circuits in accordance with the various positions of the trip valve 5| as will be described later.

The operating mechanism for the turbine governor control valve I9 may be of any suitable type adapted to be regulated during the operation of the turbinelby means of a speed responsive governor. In the drawings, the speed governor 19, adapted to be driven from the turbine shaft, is connected for adjusting a pivoted beam H. At its movable end the beam is connected to the split type floating lever 12 which, in a well known manner, through the pilot valve 13 and hydraulic operating motor 14 .effects the adjustment of' the control valve i6. Load adjustment of the governing mechanism is effected by means of a'suitable synchronizing spring 15 connectedat one end to the governor beam H, the tension or the spring being adjustable by a suitable reversible electric motor .16 through gearing 11. turbine the lower half of the split floating lever is latched in a position corresponding to the no-load, normal speed position of the control valve I6.

It is well understood that the governor regutaken over automatically by the speed goveming apparatus,.the floating lever is unlatched, and the throttle valve I5 is shifted to the fully opened position. Contacts 84 are provided on governor.

a single valve gear connected for dual control by the mechanism shown for operating valve l5 as well as by the emergency trip governor 29 shown for operating valve l4. Such modification of the schematic arrangement may be' readily made by one skilled in the art. 4

The turbine is provided with a lubricating oil system comprising a pump 9! which is connected to a suitable supply reservoir (not shown) by conduit 92 and is adapted to discharge into the oil cooler 93 through conduit 94. The pump isdriven by a suitable electric motor 95 the energization of which is controlled by a suitable switch 96 operable by solenoid 91. changer coil 98 is arranged within the cooler 99 and adapted to be suppliedwith cooling fluid through conduit 99, the flow therethrough being controlled by a normally closed valve I09 which is arranged to be actuated to the opened position by a solenoid ml. From the cooler 93 oil is distributed to the various bearings through conduit "22 and branch conduit I93, oil being drained from the bearings back to the supply reservoir through suitable drain connections exciter.

During the starting period of the lated valve of a turbine is usually of the sectional admission type. During starting of the turbine it is desirable that steam be admitted thereto through a single section of openings which may be effected by holding the floating lever in a predetermined position as by a latch mechanism. The latch 18 is normally biased to the operative position by a spring 19 and isadapted tobe actuated to the releasing position by a solenoid 8| during the running operation of the turbine. In the shutting down operation of the turbine, when solenoid 8! is deenergizsd, the latch i6 is remade when the governor beam is adjusted to the no-load position by action of spring 19.

Contacts 82 are provided which are arranged to be opened upon the latch 18 being moved to the inoperative position. It is to be understood that during the starting cycle the supply of operating fluid to the turbine is controlled by means of the'throttle valve [5 and not by the control valve it. After the turbine has been brought up to running speed, the control is (not shown). vIt' is obvious that the same lubricating system may be connected for supplying lubricant to the bearings of the generator and A device H16 responsive to oil pressure is connected to the conduit 94 and is provided with a pair of contact arms Hi8 and "29 which are adapted to close circuits simultaneously upon the occurrence of a predetermined suitable oil pressure condition.

A device Hi connected to a bulb H2 arranged within a turbine bearing housing is responsive to the bearing temperature and is arranged to open circuit the contact arm H3 upon the occurrence of a predetermined abnormal bearing temperature condition. While only one of these devices is illustrated it is obvious that itrepresents any number of similar devices responsive to the temperatures of all the various turbine and generator bearings the contacts of which may be connected in series.

'Water is adapted to be supplied to the high pressure turbine packing through conduit H5, a normally closed valve H6 being arranged thereingthe valve being adapted to be actuated to the opened position by means of a'solenoid l H. Similarly, water is supplied to .the low pressure packing through the conduit N8, the flow therethrough being controlledby a normally closed valve H9 which valve is adapted to be actuated to the opened position by a solenoid I20. Steam is also adapted to be supplied to the high pressure packing through another conduit HI, a normally closed valve I22 being arranged therein and adapted to be actuated to the opened position by means of a solenoid I23. A. high pressure packing leak-off connection 124 hasa normally open valve I25 arranged therein which A heat exvalve is adapted to be closed by solenoid I26. Contact III! is provided on solenoid I26 for indicating the opened condition of the valve.

At the beginning of the starting cycle, the

turbine of course is cold, and when steam is first admitted thereto it will condense within the casing. One or more suitably arranged and normally open drain valves I21 are provided for draining such condensate from the interior of the turbine. Such valves maybe operated to the closed position by a solenoid I28, contacts I29 being provided for indicating the open position of the valves.

The turbine is adapted to exhaust into a condenser I30, condensate being drawn therefrom by means of a pump I3I and discharged through connection I32 to the hot well (not shown), The pump I3I is adapted to be operated by means of a suitable electric motor I33, the energization of which is controlled by a switch I34 operable by solenoid I35. The switch is provided with an interlock contact arm I36 which is adapted to be closed simultaneously with the closing of the switch I34. Cooling wateris supplied to the heat exchanger tubes of the condenser by means of a pump I31, which pump is adapted to be driven by a suitable electric motor I38 the energization of which is controlled by a switch I39 operable by solenoid I40. Auxiliary contacts I of the switch are arranged to be closed simultaneously with'the closure of the switch. Just prior to the starting up of the turbine air is withdrawn from the condenser and the turbine by means of an air exhaust pump I42 suitably connected by conduit I43 with the condenser chamber. The pump I42 is arranged to be driven by a suitable electric motor I44, the energization of which is controlled by a suitable switch I45 operable by solenoid I46. Interlock contacts I41 are provided'on the switch mechanism I45 which contacts are adapted to be closed simultaneously with the closure of the switch. A normally openvalve I46 is arranged in a branch conduit I49 communicating between the condenser chamber and atmosphere, which valve is adapted to be actuated to the closed position by a solenoid I50. Interlock contacts II are provided which are adapted to close a control circuit when the vacuum breaker valve I48 is in the closed position. Pressure responsive devices I52 and I53 are provided for indicating predetermined pressure conditions obtaining within the turbine and condenser chamber, the devices being provided with contacts I54 and I55, respectively. The device I52 is adjusted to close its contacts I54 upon the occurrence of normal running vacuum obtaining in the turbine. The contacts I55 of device I53 are adjusted so that they are closed upon any vacuum obtaining within the turbine and opened at approximately atmospheric pressure occurring therein.

A suitable cooling fluid, such as air or hydrogen, is adapted to be supplied to the generator through the cooler I56 and conduit I51. A suitable cooling medium is circulated through the heat exchanger coils I56 within the cooler, the flow of cooling medium being controlled by the normally closed valve I59, which valve is adapted to be actuated to the opened position by means of a' solenoid operator I66.

A steam pressure responsive device I6I is connected to the supply conduit I3 ahead of the stop valve I4. The device IN is provided with contacts I62 which are adapted to be closed upon a predetermined steam pressure existing in the of the turbine.

A number of speed responsive switches are provided on the turbine shaft in addition to the emergency over-speed device 20. The devi e I65 is arranged for closing a set of contacts at a turbine speed of about one R. P. M. The device I66 is adapted to close its contacts at a speed corresponding to about 98% normal speed of the turbine. These devices control certain steps in the starting cycle as will be later described in connection with the control system. It is obvious that the devices I65 and I66 may be substituted by a single device having two sets of contacts operable to the closed position at the above 'mentioned turbine speeds respectively.

The generator II may also be provided with suitable protective devices for indicating any abnormal condition of operation thereof. For

' example, means may be provided for causing the any other cause.

supplying conduit and to be opened in the event shut down of the power plant at any time either during the starting cycle or during the normal running operation thereof upon the occurrence of a predetermined excess temperature condition of the windings thereof due either to anoverload or to a failure of the ventilating system, or Such means are represented in the drawings by a bulb I61 arranged within the interior of the generator and connected to an expansible unit I68 having contacts I69 which are adapted to be moved to the open circuit position upon the occurrence of a slightly overheated condition of the generator windings, and contacts I10 which are adapted to be opened upon excessive overheating of the windings. Generator over voltage protective means are also provided as will be pointed out in the description of the control system.

With regard to the automatic control system, the starting and stopping of the turbine power plant is at all times under the control of the station supervisor who may be located on the floor of the powerhouse or in a remote control room. The control system to be described contemplates that the supervisor, if located in a remote control room, he assisted in the starting and stopping of the power plant by a fioorman whose function it is to observe theoccurrence oi any accident, pipe leak of importance, or any one of the possible unanticipatory conditions that must be left to human observation and not to a planned system of control. In order to insure that the fioorman'is on the joband is properly attending to his duties, the control system is adapted for certain timely operations to be performed by the floorman. Thus, the starting cycle is broken up into a plurality of' steps each of which must be initiated by the floorman presumably after he has determined that the preceding step of the starting cycle has been properly completed and that everything is in apparent readiness for progressing with the next step.

Certain connections for the control system are effected in a step by step sequence through a motor driven drum controller having a plurality -of operative contact making positions, the conj The drum I90 carrying the various sets of segments is adapted to be rotated by steps in a direction as indicated by an electric motor HI,-

-so that there is a mechanical interlocking of being arranged to be engaged by the segments 20! to 242, respectively, the fingers 253 to 285, inc1llsiVe,-t0 be engaged by the segments 213 to 225, respectively, and fingers 266 and 261 to be engaged by the segments 226 and 227, respectively. In the schematic'wiring diagram oi- Fig.

.3 only the contact fingers oi the drum controller are shown along the left-hand'side and the connections between the various *fingcrs may be checked for the various positions of the drum by reference to Fig. 2.

Referring now to the wiring diagram Fig. 3, (A, B, C) the electrical connections for the generator II and the exciter 12 are shown in an elementary manner, the generator having armature leads 3!, 302 and 303 adapted to be concourse. be arranged in this circuit. The contacts H32 of the device it! are normally closed and will be opened in the event that the pressure of the steam supply for the turbine drops below a predetermined value. The contacts 59 of the device 58 are normally closed and will be opened in the event that the windings of the generator become slightly overheated. As the contact arm 3|! of the device 316 closes, an energizing circuit is completed tor the master control relay 3! which circuit extends from the positive of the source of supply through the drum controller finger 24!, segments 201, 282, finger 242, through the closed contacts 3H, the winding of relay 3l8, and through the contacts of the protective devices which will cause the immediate shutdown of the unit in case of accident while the machine is running. Among such protective devices may be the generator temperature responsive device 168, having contactsilfl which will open upon excessive heating of the generator windings. The contacts -I I3 of the bearing temperature responsive device Ill, contacts 255 of the generator overvoltage responsive device 295, and contacts of the emergency governor mechanism 20 may also be arranged in this circuit as nected to the station buses 304 by a circuit breaker 305. The circuit breaker 305 may be of tion, these leads will be merely referred to as the positive and negative supply leads. When it is desired to start up the power plant the supervisor closes the start and stop control switch 3l2 and the doorman, indicating that everything is in readiness, presses button 3| 3 which initiates the first step of the starting cycle. While the start indication is here provided by manual control switches, it .will be obvious that the start indication, as well as the stop indication, may. be provided by any suitable switch device receiving an operating impulse from any suitable control source. Relay 3 picks up its arm 3 I blocking itself in around the contacts of the button 3i3. An energizing circuit is completed for the winding of the control relay 3l5 through the contacts of a number of protective devices which are included in this circuit and which will cause the generator, after it is connected to the line, to be unloaded slowly until the condition no longer exists, or if it continues, until the plant is shut down. Among such devices .may be the steam pressure responsive device I6! and the generator temperature responsive device I68. Contacts of other ,pre-emergencyprotective devices may, of

well as contacts of other suitable emergency protective devices. relay 356 are bridged when the power plant is in normal running operation through line 319, contacts 34 associated with the speedgovernor beam H, and contacts 320 of the circuit breaker position responsive device 23! for reasons as will become apparent as the description proceeds. The device 29! is energized through-a set of auxiliary contacts 292 on the main circuit breaker 305. The contacts 292 are closed when the circuit breakers are open, and open are closed.

Segments 202' and 202' of'the drum controller engage the associated finger 242 only in the off and shutting down positions of the drum, respectively, so that the master control relay 3|3 cannot be moved closed except in these two positions of .the drum. The relay 318 seals itself closed through its contactarm 32i, the drum contact finger 243 and segment 203. In the running position of the drum, when neither segments 202 nor 233' are in a contact making position, the relay 3l3 is sealed in through the contacts H4 01 the vacuum responsive device I52 and the contacts N3 of the bearing oil pressure responsive device I36. It is understood that initially the contacts of the latter two devices are open since running vacuum has not as yet been established within the. turbine, and the lubricating oil pump not yet started. During the normal running operation of the turbine, in the event'that either the vacuum or the oil pressure fails, the master relay 3" will be deenergized and the power plant will be immediately shut down. i g

The contact arm 322 oi the relay 3!! completes a circuit for the relay 323 which relay seals itself in through its contact arm 323 and the finger 2N and segment 2040f the drum controller. When the relay 323 moves its contact am 325 to the upper position an energizing circuit is completed for the drum controller segment 2|3. This energizing circuit extends from the positive of the source of supply through the closedupper contacts 326 of relay 323 -to the drum controller finger 253 and segment 213. The drum controller motor l9! isthereupon energized to rotate the drum to the starting position. This energizing The contacts 3!! of the control when the circuit breakers will be established for energizing vario'us auxiliaries including the air pump, water pump, condensate pump, stop valve, and the vacuum breaker valve. These circuits extend from the energized segment 2I5 through the contact finger 255, to the operating solenoids I46, I40, I35, I8, and I50, connected in parallel, to the negative supply line. pump motors I44, I38, and I33, respectively, will be started, the stop valve I4 will be moved to the opened position, and the vacuum breaker valve I40 will be moved'to the closed position.

Another circuit will be completed simultaneously from the energized segment 205 of the drum controller through contact finger 245 for energizing the switch operating solenoid 91 which, in turn, will effect the energization of the oil pump motor 35. When suitable oil pressure is built up, contacts I09 of the pressure responsive device I06 will move to the closed circuit position completing a circuit for causing the admission of live steam to the turbine for warming it to operating temperature. The control circuit for causing the operation of the throttle valve I5 to the first open position extends from the energized segment 2 I I through the contact finger 251. through the closed limit switch H of the turbine throttle valve operating mechanism, the closed contacts and I29 of the high pressure packing leak-oil? valve I26 and the drain valve I21, respectively, indicating that these valves are open, the closed contacts 82 oi the governor latch I6, the closed contacts I08 oi the oil pressure responsive device I06, the closed contacts I41, Hi, and I36 of the switches I45, I30, and I34, respectively, and the closed contacts I3 of the stop valve I 4, the closed contacts II of the vacuum breaker valve I40, the winding of relay 33I, the

I ture but not sufiicient to start it rolling.

, terlock contacts of the various auxiliary devices The air, water, and condensate The heating period of the turbine is measured by a suitable time delay relay 334 provided with a restraint device indicated at 335. While the restraint device is indicated as being a single dash pot, it is obvious that any other suitable device is indicated thereby. Since the warm up period may cover as much as two hours, it may be desirable to use a clockwork or motor driven timing device instead of a dash pot. It is-equally ob- I vious that the action of this device may be modified by means responsive to the turbine tempera- At the same time that the limit switch 4| opens,'the limit switch 42, will close which will complete an energizing circuit for the time delay relay 334. After a predetermined time, as measured by the setting of the restraint device 335, sufficient for warming the turbine has expired, the contacts 336 will closecompleting a circuit to open the-throttle valve slowly to the turbine starting or rollingposition. This circuit tric motor 345 which may be energized from any I suitable power source such as the station buses 304, through the transformer 346. The energizing circuit may be traced from the right-hand terminal of the secondary winding of the transformer 346 through lines 341, 343, the motor 345, the closed contact 349 of the master control relay 3l6, lines 350, 35! and 352 to the left-hand terminal of the transformer secondary winding. The motor is adapted for driving through suitable speed reducing gearing 355 a plurality of intermittent switches 339, 355, and 351 for intermittently completing a plurality of corresponding circuits. Each of the intermittent switches may comprise a disk 358, see Fig. 4, of insulating material, having a pair of diametrically opposite segments 359, 360 connected'together as at 36L As the disk is slowly rotated, a circuit is intermittently completed between the brushes 362 and 363. The periods of circuit making may be varied by shifting one of the brushes, or by varying the length of the segments. It will become obvious as the description proceeds that the tapping device 340 may be substituted by any other suitable device performing a similar function.

1 As the switch 339 intermittently energizes relay 33I, the pilot motor 33 is correspondingly energized to tap the throttle open relatively slowly. When the turbine starts to roll, the low speed switch I65 will/close its contacts to energize the relay 31I through the contact finger 253 and drum controller segment 2I8. The relay 3' will seal itself in through the closure of itscontact3l2 which establishes a circuit around the contactsof the speed switch I65. As the contact 313 of the relay 3'" moves to the closed circuit position, the latch tripping solenoid 62 for the throttle valve trip valve 5| is energized through the closed position switch 64. latch 59 is moved to the releasing position, the trip valve 5| will move upwardly under force of spring 55, uncovering the port of the pipe 53 allowing operating fluid to circulate around the piston 22 of the throttle valve operating motor 23. Under the force of the spring 24 the throttle valve I5 will be moved to the closed position. When the valve 5I is tripped, the position switches 64 and 65 are opened while the position switch 63 is closed. The latch tripping solenoid 62 is deenergized upon the opening of the position switch 64.

The closed contacts 314 of the relay 3' will eilect the energization of the drum controller motor I9I to rotate the drum to the next, or first check position. This control circuit extends from the energized drum segment 2I6, through As the the closedof relay 321, to the negative supply line. Asthe relay 321 picks up, the drum controller motor I 9I will be connected across the supply lines and will rotate the drum until segment 2I9 disengages the contact finger 258.

At this point, the automatic progression of the starting operation is interrupted to interpose a manual check by the doorman to indicate that the auxiliaries are functioning properly, that the turbine operated smoothly, and that everything is in order for bringing the turbine through the nextsucceeding stages. If the fioorman is satislied in these and other respects, he will press a button 3i5l to energize the manual check relay 382. It is obvious that the manual check button maybe substituted by any suitable automatic checking devices well known in the art, such as devices responsive to excessive vibration, shaft eccentricity, or rubbing of the internal turbine parts. In such event, the contacts of the button 394 of the relay 382,'lines 395, 311, winding of relay 32'! to the negative supply line. As the relay,32'l picks up, the drum controller motor- I9! will be connected across the line, which will operate the drum until the segment 2I9 disengages the contact finger 259. This position of the drum will effect connections for bringing the turbine to speed.

The throttle valve trip' mechanism will first be reset by the energization of the throttle valve adjusting motor 33 for operation in the reverse' direction. ,This control circuit will extend from the energized segment 206 through contact finger 233, throttle valve limit switch 45, the winding of relay 338, the closed contact of the position switch 53 to the negative supplyline. As the relay 383 picks up, its contact 389 will complete an energizing circuit for the reverse directional winding 399 of the throttle valve pilot motor 33.

The lower end of the plunger 35 will engage with the upper end of trip valve stem 52 and drive it downwardly until it is engaged by the latch 59. At this position of the trip valve, the position switch 53 and limit switch 46 will both be moved to the open circuit position thereby deenergizing the relay 38B and stopping the motor 33. The position switches 94 and 55 will be closed as trip valve 5I is reset. The throttle valve limit switch 4I will also be closed at this time and the previously described circuit will be completed for relay 33I which will energize winding 333 of pilot motor 33 to operate the throttle valve to the warming up position when the limit switch 4| will be reopened and limit switch 42 reclosed. As

termittent switch 339 and the throttle valve will be slowly tapped open again. This time, however, the opening of the throttle valve will continue until the limit switch 43 opens. The low speed switch I 65 will be ineflfective for energizing the trip coil 62 now because in the present position of the drum, the contact finger 258 is disengaged from its segment 2I8 and hence relay 3' will remain deenergized. The switch :13 is adjusted to open at a position of the throttle valve corresponding to some intermediate turbine speed, for example, about 400 revolutions per minute.

-It will be noted that contact finger 241 was energized by its associated segment 201 simultaneously with the energization of finger 245. The solenoids IOI, I I1 and I29 are energized for opening the lubricating oil cooling water valve I09 and the water valves I I6 and IIS to the high and low pressure turbine packings, respectively. The controller segment 291 and finger 241 are bridged by the contact I of the condenser vacuum responsive device I53 which device is so adjusted to maintain water in the packings until vacuum becomes atmospheric on shutting down. It is to be understood that the device I53 does not close its contact until normal running vacuum condition obtains, within the condenser. A circuit is also established through segment 229 and finger 269 for energizing'the solenoid I23 and opening the valve I22 so as to admit steam to the turbine highpressure packing.

Another circuit was also established by the last'shift of the drum controller from segment 22!, through the contact finger 2H for energizing the time delay relay 39L At the end of this time delay which allows the turbine a definite time to warm up operating at 400 R. P. M., the relay 39I closes its contacts 392 establishing a circuit around the limit switch 43, the opening of which stopped the throttle valve in the 400 R. P. M. position, to cause the throttle valve to be opened further'to allow the turbine to come up speed, which will be a relatively short time after the closure of the relay 39I, the voltage of the exciter I2 will normally be sufiicient for connecting it to the field winding, of the generator II. The winding of relay 40 I directly connected across the exciter buses 402 and 403 through connections 494 and 495 is so adjusted that it will pick up and close its contacts upon the occurrence of a predetermined suitable exciter voltage. In the deenergized condition of relay 4III, its contact arm 49! closes a circuit through lines 408 and 499 cutting out a portion 4I0 of the exoiter shunt field resistance M I. The exciter field and hence, the voltage, will thus tend to pick up rapidly upon the increase of turbine speed. As relay 4M picks up and opens the contact 491, the full normal resistance will be inserted in the exciter shunt field circuit.

As relay 491 closes its contact 414 an energizing circuit is completed for the winding of the generator field contactor 485. This circuit extends from the positive supply line through the closed contact MS of the master control relay 3 I 8, the closed contact 4 I4 of relay 49 I, the closed contact 4Il. of the generator auxiliary field contactor 4| 9, the winding of the contactor M5 to the negative supply line. Contact arm 4|! contactor 4l5 completes a locking circuit for contactor 5 around contact 4 of relay 4!. The field contactor arms 42l, 422 connect the exciter I2 to the generator field winding slip-rings 308 tends from one exciter terminal through line 403, contactor arm 42l, connection 423, line 424 to generator slip-ring 308. The other side ofthe excitation circuit extends from the second exciter terminal through line 402, contactor arm 422, line 429, rheostat arm 426, field rheostat 425, line 421, the winding of field failure responsive relay 428, line 430, to the generator slip-ring 300.

If for some reason or other, the exciter voltage does not build up as it normally should within a predetermined time, provision is made for automatically connecting an auxiliary source of excitation to the generator field winding.

Simultaneously with the energization of the previously described time delay relay 3!, a sec- 0nd time delay relay 436 is energized by a .circult extending from the energized drum control.- ler segment 22!, contact finger 26l, winding of relay 436, line 431, contact 438 of the contactor 8, contact 9 of the contactor M5 in its lower position to the negative side of the source of supply. If proper voltage of exciter I2 is present and relay 405 p s p. then the field contactor 4i5 will be energized, contact 4i9 will be raised to its upper position and time delay relay 436 will bedeenergized before it picks up. Assume, however, that at the end of the delay period of relay 436, which is somewhat longer than the period of relay 39l, the potential of exciter l2 has failed to build up and that the relay 40! and hence also field contactor 415 remains deenergized. The time delay relay 436 closes its contact 439 thereby establishing an energizing circuit'for the auxiliary field contactor M6. The energizing circuit for the latter extends from the positive of the source of supply through the closed contact 416 of the master control relay 3i8, line 440, thecloscd contact 439 of the time delay relay 436, the winding of the contactor 410, the

and 309. One side of the excitation circuit ex-;

'ing of relay 462 across the supply lines.

moves to the open circuit position, either of which will break the shunt circuit including the resistance 448. i 4

Upon the connection of the generator, field winding to-either the exciter l2 or the auxiliary source of excitation, the supply ofcooling water to the generator ventilating air cooler I56 will be initiated. The operating solenoid I60 forthe water fiow control valve I59 will be energized by a circuit extending from the positive of the sourceof supply to the winding of the solenoid I60 through eitlier of the closed contacts 452 or 453 of the field contactors H5 or 410, respectively, to the negative of the source of supply.

At about 98% turbine speed, the speed switch I66 will close its contact 46! to connect the wind- As the relay 462 picks up its arm 463, the contact making voltmeter, generally indicated at 464, will be connected to commence the adjustment of the generator voltage. The contact making voltmeter may be of any suitable type and is illustrated in a diagrammatic manner as comprising a voltage responsive element 465 which is connected across the generator leads so as ,to actuate its movable contact making arm 466 in accordance with the generator voltage. As indicated, the winding of element 465 is connected through leads 461 and 468, lines l and 469-to the secondary winding of the potential transformer 410, the primary of which is in turn connected to the generator leads 302 and 303. The

. contact making arm 466 is fioatingly arranged and is adapted to engage with either of a pair giaoppositely arranged fixed contacts 412 and The contact making arm 466 of the voltmeter is energized upon the pick-up of either of the field contactors 415 or 8 through their contacts closed contacts 442 of the field contactor 5 to I the negative of the source of supply. Upon the pick-up of the auxiliary contactor 8, its contact'4l1 open circuits the winding of the main field contactor M5 to preclude a later connection of the exciter to the field winding of the generator. The contact 438 of the auxiliary contactor also rises to deenergize the time delay relay 436 while the contact 443 of the auxiliary contactor closes to establish a holding circuit for the auxiliary contactor around the contact 439 of the time delay relay 436 before it drops out. The

contactor arms 444 and 445 connect the auxiliary source of excitation, indicated bybuses 446, to the generator field through lines 424 and 429.

414 or 415, respectively. The circuit extends from the contact finger 253' of the drum controller through the contactor 416 and through either of the closed contacts 414 or 415 to the voltmeter contact making arm 466. Assume now, for example, that the generator voltage is below the desired value, or line voltage, and that the excitation is to be increased to raise the generator voltage. The contact arm 466 will then be actuated to engagewith the fixed contact "2 thereby completing an energizing circuit for the contactor 48l which picks up to effect the energization of the reversible rheostat adjusting motor 482 through thedlrectional field winding 483.

The circuit for the winding of contactor 48l ex- The contact I of the circuit breaker position indicating device 291 is in the open circuit position at this time. After the generator is connected to the line. this contact will be closed for 7 reasons as will be described in connection with the description of the shutting down operation.

Prior to the connection of excitation thereto, the generator field is shunted by a discharge resistance 446. 'The resistance circuit extends from line 424, through line 441, resistance 446, arms 45! and 449 of contactors M8 and H5, respective-v ly, to line 430. Upon the pick-up of the exciter field contactor M5 the contact 449 moves to the open circuit position whereas upon the pick-up oi! the auxiliary field contactor M8 the contact 46l tends from the contact finger 253' of the controller through the closed contact 416, either of the contacts 414 or 415 of the field contactors,

through the floating contact arm 466 of the voltmeter, through the closed contacts 463 of the relay 452, the winding of the contactor 48!, through the limit switch 484 and line 485, to the negative of the source of supply. As the contactor 481 picks up, its arm 486 completes the circuit for the field winding 483 of the motor 462. The motor 482 will slowly rotate the movable arm 426 of the rheostat in a counterclockwise direction increasing the excitation current until the generator voltage reaches the desired predetermined value at which time the floating arm 466 of the voltmeter 464 will disengage the fixed contact 412. If, due to some abnormal condition, the movable arm of the rheostat 425 should reach its limit of travel before the'contact arm of the voltmeter disengages the fixed contact 412, the rheostat motor 482 will be deenergized by the I The second arm 603 of relay 604 will complete a movement oi the limit switch 464 by rheostat arm 426 to the open circuit position, thereby deenergizing the contactor 46L Assuming that the generator voltage shouldrise above the predetermined value, the floating arm of the contact making voltmeter will engage with the fixed contact 413 thereby completing an energizing circuit for the contactor 433 which will reverse the direction of rotation of the rheostat motor 482. This energizing circuit will extend from the energized voltmeter arm 466 through the winding of the contactor 436, through the limit switch 439, to the negative of the source of supply. As the contactor 433 picks up its arm 49L the motor winding 492 will be energized causing the motor and the movable arm of the rheostat 425 to be rotated in a clockwise direction increasing the circuit resistance until the generator potential has been decreased to the desired value or, in the unusual case, until therheostat arm engages with the limit switch 489, thereby stopping the driving motor.

when the previously described relay 462 picked up, a second contact arm 493 thereof effects the energization of a time delay relay 494 through a circuit extending from the segment 222 of the control drum through the finger 262, and the closed contact 493 to the negative supply line. The dashpot, or other restraining device, of the time delay relay 494 is so adjusted that the relay control circuit for eflecting the advancement of the drum controller to the end of segment 223 or to the synchronizing" position.

will not close its contact until after the turbine is'up to full normal speed and is under control of its speed governor 10. When the time delay relay 494 picks up, its contact 495 connects lines 331 and 393, which establishes a short circuit across the intermittent switch 339 of the tapping device 340. The throttle valve is then opened rapidly to the full open position and the position switch 44 0! the throttle valve operating mechanism moves to the contact making position energizing the' relay 496. The relay 496 seals itself in upon the closure of its arm 49! which establishes a circuit bridging the limit switch 44. A second arm 496 of the relay 496 completes a circuit foradvanclng the controller to the end of the'segment 222 or to the second check position.

496, connection 499, line 311, drum motor control relay 321, to the negative of the source of supply.

As the segment 208 of the drum controller engages with the contact finger 243, the throtthe key 502. When the turbine speed has dropped to such a value below 98% that the speed switch I66 moves to the open circuit position, the relay 462 will be deenerglzed allowing its contact arm 503 to move to the circuit closing position. When this occurs, an energizing circuit will be completed for the manual check relay 504 which circuit' will extend from the drum segment 223, the contact linger 263 through the closed contact 503, winding of the manual check relay 504, the contact of the push button station or key 502, to the negative of the source of supply. As the manual check relay 634 picks up, its arm 566 will establish a circuit around the key' 502 to lock the manual check relay in the energized position.

Suppose that some unforeseen condition has unduly delayed the progression or the starting cycle up to this point making it desirable that the attention of the station supervisor be. directed to such fact. Provision is made so that if the manua1 check button 602 is not depressed within a certain time after the starting operation is initiated, a signal will be given. When relay 3i6 picked up at the commencement of the starting cycle, its arm 454 closed to complete an energizing circuit extending from the positive supply line through arm 501 of relay 504, for the winding of time delay relay 456. The restraint device 451 is adjusted so that the relay contact arm 456 will not be permitted to close until a predetermined time following the initiation of the starting cycle as measured 'by the time normally required for bringing the turbine up to full running speed and indicated by the advancement of the drum to the second check" position. In the event that the operation of the turbine has not progressed in a normal manner within this period, the contact 453 will close completing a. circuit for the signal 469 which may be a bell, light or othersuitable device.

But assuming that the progressionwas. normal and that button 502 was depressed advancing the drum to the synchronizing position, then the valve operating mechanism is first reset preparatory to the moving of the throttle valve l6 again to the fully opened position. A circuit is completed by the drum controller in its new position extending from a segment-333" through finger 246, pontion switch 46, contactor 333, trip valve position switch a, m the negative oif'the source of supply. The contactor 333 closes its arm 339 to energize the directional winding 393 of the motor 33 which, as previously described, lowers the stem 36 which, in turn, resets the trip valve 6|. As the trip valve isreset, the position This circuit extends from the energized {finger 262, through closed contact 493 of relay switch 63 opens to deenergize the contactor 333 and to stop the motor 33. The trip valve position switches 34 and 66, of course, are reclosed.

as the trip valve is reset. The controller segment 224 and contact finger 234 complete a circuit extending through lines 633, 639, the position switch 43, line 343, the various auxiliary interlocks-tor energizing the contactor 33L The throttle valve control motor 33 is thereby continuously energized through its winding 333 and eflectsrapid opening movement of the throttle valve I6 until it reaches the 400 R. P. M. position, when the position switch 43 opens. The opening of the position switch 43 disrupts the continuous energization of the throttle valve control motor which motor will thereafter be intermittently energized through the intermittent switch 366 oi the tapping device 349. This energizing circuit will extend from the drum controller finger 264 through line 503, the intermittent switch 366 of the tapping device 343, line 6I0,-'line 343, through the interlocks of the various auxiliary devices to the winding of the control contactor 33L The intermittent switch 366 is so adjusted that it will eflect an opening movement of the throttle valve to the full open position at a rate faster than would the intermittent switch 339 yet not fast enough to harm the turbine. It will be noted that'during this step, the excitation will remain connected to the generator fleld,'

since once either of the field contactors H6 or 418 is energized, it is sealed in the operative position. When the turbine again reaches 98% speed, the speed switch 166 and the associated auxiliary relay 462 will close. At about this turbine speed,

the governor 16 will automatically take over the control of the turbine speed through the regulation of the valve 16, and the throttle valve is moved to the inoperative or full open position at which time limit switch 45 opens to deenergize the motor 33.-

The turbine is now operating at full normal speed under the control of the speed governor 16 and everything is in condition for matching the speed of the turbine withthe frequency of the line to which the generator is to be connected. The closed contacts 514 and 515 of the circuit breaker position responsive device 291 and the closed contacts 516 and 511 of the auxiliary contactor 462 completeenergizing circuits for the speed matcher 518. The speed matcher 518 may be of any suitable type, a number of such devices being well known in the art, one

of which, for example, is fully described in the Patent No. 1,843,788 issued February 2, 1932, to Harold T. Seeley and assigned to the General Electric Company, the assignee of the present application. Such devices commonly embody one element which is adapted to be energized with one potential and a second element rdapted to be energized with the second potential which is to be matched with the first. A floating contact, arm is energized by a difierential component of force which is proportional.to the differential in the frequency of the two potentials being matched. One circuit which supplies the speed matcher 518 with the generator potential extends fromone terminal of the potential transformer 416 through line 469, connection 519, the speed matcher 518, line 526, the closed contacts 511 and 515 of the devices 462 and 291, respectively, and through line 351 to the other terminal 'of the potential transformer 416. The second circuit which supplies the speed matcher with line potential extends from one terminal of the potential transformer 346 through line 341, connection 521, the speed matcher 518, line 522, the closed contacts 516 and 514 of the devices 462 and 291, respectively, and through lines 351 and 352 to the other terminal of the potential-transformer 346. The speed matcher 518 regulates the synchronizing motor 16 of the turbine governor to bring the generator to the correct speed for synchronizing. The regulating circuit for the motor 16 is made through the drum controller segment 269, contact finger 249, the intermittent contact arm 523 of the speed matcher 518, through either of the fixed contacts 524 and 525 to the directional windings of the motor 16. When the intermittent contact arm 523 is in engagement with the fixed contact 524, the energizing circuit is completed through line 526, the closed contact arm 521 or the control relay 316, line 528, through field winding 629 of the motor 16 to the other supply line.

When the contact arm 523 engages with the fixed contact 525, the directional winding 536 of the motor 16 is energized.

When the speed of the generator has been adjusted so as to correspond with the frequency of the line voltage, the synchronizer 532. will effect the connection or the generator to the line through the circuit breaker 365. The synchronizer 532 is connected in parallel with the speed matcher 518 through lines 533, 534, and 469, 341.

The automatic synchronizer 532, examples of determined values.

erator 11 and the system 364 are less than pre- As indicated, the synchro-' nizer 532 includes contacts 538 which when closed complete an energizing circuit for the control contactor 539. The energizing circuit for the contactor 539 may be traced from the negative of the source of supply through line 541, contact arm 554 of the control relay 318, contact finger 266 of the drum controller,- segments 226 and 221, contact finger 261 of the drum controller,

through the closed contacts 542 of the field device 291, line 545, through the contact 538 of the synchronizer 532, through the winding of the relay 539 and line 546, to the positive of the source of supply. As the relay 539 picks up, its arm 541 locks the relay in around the contact 538 of the synchronizer while its arm 548 completes an energizing circuit for r the circuit breaker operating solenoid 366. The latter circuit extends from the energized drum contact finger 261 through the closed contacts 542 and 543 of the relays 428 and 462, respectively, line 513, to the closed contact 548 of the. device 539, line 549, the closed contacts of the emergency circuit breaker tripping device 546, the winding of the circuit breaker closing solenoid 366, to the positive of the source of supply. Relay 551, connected between line 549 and the positive supply line is also energized upon the pick-up of relay 639. As the relay 551 picks up its arm 552, a holding circuit for the circuit breaker coil 366 is established around the contact 548 of the control relay 539 from drum finger 261, through contacts 542 of relay 428 through line 553,'arm 552 of relay 551 to line 549.

It will be noted that as the circuit breaker 365 is actuated to the closed position, its auxiliary contacts 292 are opened to disrupt the energizing circuit for the device 291. As the device 291 drops out, its contacts 326 and 441 close to complete circuits that will be described later, its contact 416 will move to the open circuit position, deenergizing the voltmeter 464, while its contacts 555 close to complete an energizing circuit for the drum controller motor 191 whereby was shifted to the running position, the segment 226 disengaged the associated contact finger 266, thereby deenergizing the solenoid 123 and allowing the valve 122 to move to the closed position thereby cutting 01! the steam to the. high pressure packing. The drum controller in its new position completes an energizing circuit extending to the closed pofition, and the governor latch,

II to the releasing position respectively.

Segment III of the-drum controller through the contact finger 25. connects the voltage and load control 01' the main generator to push buttons on the supervisor's cabinet.- The push but-- tons iii and 582 are arranged for adjusting the turbine governor synchronizing spring through the control of the motor 15. To increase the generator load, the button I is depressed thereby completing a circuit for the contactor 563 which picksup its arm I to complete a circuit extending from the energized drum controller finger "I, line 565, contact I of the'contactor I, lines 565, 52', the closed contact 521 of the master controlsrelay 3|, line 528 for winding "To! the moton'li. When the generator load has been suiliciently-increased, the button I may be released thereby'deenerigizing the contactor I which drops out to deenergize the motor Ii. Similarly, if it is desired to decrease the generator load, the button 562 may be depressed thereby energizing the contactor 581 which will pick up its contact 568 to complete an energizing circuit extending from the energized line 565 through line 569 to the winding ill of the synchronizing spring adjusting motor II. Whenthe generator load has been suitably turbine governor is adjusted to the no-load position. It is to be understood, of course, that during the unloading of the turbine, the generator field excitation should be properly adjusted diminished, the button 582 may be released there- -by deenergizing the contactor m and; accordmaybe controlled ingly, the motor ll,

The voltage at the generator I by manipulation of the buttons ill and 512. To

raise the.generator voltage, the button "I may be depressed thereby completing a circuit from the energized dine III through line 813 for the contactor lit, which, as previously described, picks up to nergize the winding 4" of the rheostat m or 4|! to decrease the resistance in the generator field circuit. Upon the predeterincrease of the generator voltage, the button "I'll may be released thereby arresting further adjustment of the rheostat. Similarly, to decrease the generator voltage, the button 512 may be depressedthereby completing a circuit from the energized line 565 through line '8' for the contactor 488 which picks up to complete an energizing circuit for the field winding 492 of the rheostat motor 482. The rheostat 425 will thereupon be adjusted so as to increase the amount of resistance in the exciter circuit, thereby decreasing the voltage of the generator. Upon a predetermined decrease of the generator voltage, the button 512 may be released thereby stopping the further adjustment of the rheostat. The supervisor may effect a shut down 01' the power plant by turning the control switch in to the open circuit or stop position. This will deenergize the relay 316 whichwill drop out and close itscontacts 588 to connect the intermittent switch 357 of the tapping device M0 to operate the governor synchronizing spring motor 78 in the unloading direction. This control circuit may be traced from the energized contact finger I" of the drum controller through line 565, the closed contact 68!! of the relay 316, through line "i, the contacts of the intermittent switch til, lines 582, I, to the field winding 530 of the motor It. The motor 16 will be operated rather slowly depending upon the adjustment of the by means of control buttons ill and 512 so that the generator will carry its approximate proportion of wattless component. At the no-load position of the governor, the switch 84 associated with the'governor beam will open thereby deenergizing the master control contactor 318. As the contactor it. drops out, its contacts I move open, thus breaking the energizing circuit for the circuit breaker operating solenoid I06 causing the circuit breaker 80! to drop to the open circuit position and disconnect the generator from the line. The contact arm-583 or the master control contactor 3 establishes a circuit which will advance the control drum to the shutting down position. This latter circuit extends from the drum controller segment 2 through the contact finger 25!, through the closed contact 583 of the relay ill, line 81.1, to the drum motor control relay 321. The drum operating motor will advance the control drum to the end of'the segment 2| I, the shutting down position.

The field excitation is disconnected from the generator when the main circuit breaker is opened. With the opening of the circuit breaker 306, the circuit breaker position responsive device "I is energized again, which will cause the opening of itscontact I and which, in turn, will effect the deenergization of either field contactor ll! or Ml, disconnecting the excitation from the generator and connecting the discharge resistor I across the generator field. The dropout of either contactor lll or I" will deenergize the operating solenoid l6! ofyalve I to shut oil. the generator air cooling water. Segment 2.8 01' the drum controller will engage with the contact finger I, completing an energizing circuit for the tripping solenoid 62. As previously described, the energization of this device will resuit in movement of the throttle valve II to the closed position.

The drum controller in moving to the shutting down position deenergizes the contact finger ,2 by shifting the end of segment 2 therefrom. Relay as is thereupon deenergized which drops out to deenergize the drum segment 2" and the associated control relaysior the various pieces of auxiliary apparatus to restore them to the inoperative position. The motors tor the air pump,

' water pump, and condensate pump of the condenser are deenergized. Stop valve i4 is closed, and the condenser vacuum breaker valve H8 is opened. By the disconnection of contact finger 256 from the drum segment I", the high pressure packing leak-ofij valve I25 is opened, the drain valve i2! is opened, and the latch 18 is released to reengage with the end of the floating lever 12 of the governor mechanism. When the condenser vacuum rises to substantially atmospheric pressure, the vacuum. responsive device ii! will open its contact it! to shut on the high and low pressure packing water and the cooling water supply to the oil cooler. Inthis position of the controller, segment 2!: thereof engages with the contact finger 252 to energize .the time delay relay "5 which is so adjusted that it will not pick up until after the turbine has stopped. At the end of the time delay of the relay 595, it closes its contact arm 5&8 to connect finger 252 of the drum to line 8'" which will energize the drum motor 194 to adcontacts or the intermittent switch 35'luntil theJo-vance the drum to the end of segment 2!: whi

is the off position. As the end of the controller drum segment 205 disengages the contact finger 245, the oil pump 9| which has been maintained in operation as long as the turbine was rotating is shut down.

This description of the operation of the con-, trol system proceeded from the start upon the assumption that the throttle valve and the associated apparatus were initially in the set position. It will be observed, however, that following a shutdown operation as described above, the trip valve 52 is released in the shutting down position of the drum upon the engagement of segment 208 with the contact finger 248. It is obvious that before a subsequent starting can take place in the manner described, it is necessary that the throttle valve control mechanism befii'st reset. For this purposea segment 206" is provided on the drum controller which in the start position thereof engages with the contact finger 246 to complete a circuit through the position switches 46 and 63 for the relay 388. In a manner as previously described, the relay 388 when energized closes the contact 389 to effect the energization of the directional winding 390 of the motor 33, which, in turn, will restore the trip valve I to the set position. When this occurs the position switch 63 associated with the trip valve 5| will move to .the open circuit position, deenergizing the relay 388 and stopping the motor 33. The position switches 64 and 65 of the trip valve will be moved to the closed circuit position and the various position switches 4| to 46, inclusive, of the throttle valve control mechanism will be restored to the proper positions so 3 I 8 will be broken to cause that contactor to drop out and close its contact 583 to effect the shifting of the drum controller to the shut-down position. 'At the same time, the opening of .the contact 554 will effect the opening of the main circuit breaker 305, thereby disconnecting the generator from the line.

Upon the occurrence of an extreme emergency or vital abnormal condition of operation of the power plant,'the main line circuit breaker will be tripped immediately as well as the turbine throttle valve, and the various auxiliaries except the oil pump will also be immediately shut down. Thus, for example, upon the opening of either contact H0 of the generator temperature responsive device I68, contact H3 or the bearing temperature responsive device III or contact 285 of the generator voltage responsive device 296, the relay 323 as well as the master control contactor 3I8 will be deenergized. As described above, the dropout of the master control contactor will effect the immediate tripping of the mainline circuit breaker and the shifting of the drum controller to the shutting down position. Upon the dropout of relay 323 its contact arm 326 in its lowermost, position will establish a circuit from the supply line 3) through lines 500, 5! for energizing the tripping solenoid 62 to cause immediate closure of the throttle valve I 6..

The contact arm 326 of relay 3Z3 moving from its upper contact deenergizes the drum controller segment, H3 and accordingly, all of the various that the starting sequence may take place in the manner described. I

If, during the running operation of the power plant, a pie-emergency condition occurs such as a predetermined drop in the pressure of the steam supplied to the turbine, or upon a slight rise in temperature of thegenerator, the power plant will be shut down in substantially the same manher as described above. Upon the opening of the contacts of the pre-emergency devices such as the contacts I62 and I69 of the devices I6I and I68, respectively, the circuit for the relay 3I6' will be opened just as though the supervisory control switch 3I2 were opened.

It will be noted that in the event the preemergency condition disappears before the generator is completely unloaded and before the governor beam contacts 84 are opened, the shut down of the turbine may be precluded by the pressing of the button 3I3. Thus, for example, suppose that the contact I62 of the steam pressure responsive device l6I had opened indicating such as a loss of condenser vacuum or oil pres-- sure, the power plant will be shut down without first removing the load from the generator. Thus upon the opening of contact I54 of the condenser vacuum responsive device I52 or contact I08 of the oil pressure responsive device I06, the holding circuit for the master control cont-actor power plant auxiliary units' energized therethrough.

It is-to be understood that in a final embodiment of the invention, a suitable auxiliary annunciator system may be incorporated in the control system for the purpose of keeping both the supervisor and the floorman fully informed askto the progress of the starting and running operation of the power plant. Such annunciator systems, however, are not broadly new in the art and since it is not an essential part 01' the present control scheme, it has been omitted in order to limit this specification to a description of the more essential phases of the control system.

Having described the principle of operation or our invention, we desire to have it understood that the apparatus shown is merely illustrative and that the invention may be carried out by other means.

What we claim as new and desire to secure by Letters Patent of the United States, is:

1. In combination an elastic fluid turbine, valve means for admitting operating fluid to said turbine, means for adjusting said valve means in ,the open direction for accelerating said turbine slowly from standstill to normal running speed,

' governor means for regulating the flow of operating fluid to said turbine during normal run- I ning operation of said turbine, means for restraining said governor means in a predetermined intermediate position during the starting of said turbine, and means rendering the restraining means ineffective and to permit operation of the governor means at a predetermined turbine speed.

2. In an automatic control system for an elastic I fluid turbine, a first valve for controlling the 7. In a control system for a prime mover, a governor mechanism, a valve adjustable by said governor mechanism ior normally regulatingthe supply of operating fluid to said prime mover during normal running operation thereof, a secand valve ior controlling the supply or operating fluid to said prime mover, actuating means for opening said second valve, a tripping means for said second valve to cause the closure thereof,

means responsive to a predetermined abnormal condition of operation of said prime mover during the running operation thereof for releasing said turbine for regulating the supply of elastic fluid thereto, a second means in series with the first means for controlling thediow of elastic fluid to said turbine independently oisaid governor, means responsive to a start indication for operating said second means for relatively slowly accelerating said turbine from standstill to nor-,

mal running speed, and means responsive to a predetermined abnormal. condition pertaining to said turbine for shutting oil the supply or steam is said turbine independently of the condition Y of adjustment of said second means or said governor. I

4. In an automatic control system for a prime mover, means ior giving start and stop indications thereto, a governor m, a valve normally adjustable by said governor mechanism for regulatingthe flow 01' operating fluid to said prime mover during normal running operation thereof, a second valve for controlling the supply of operating fluid to said prime mover, motor means for operating said second valve, tripping means for closing said second valve independently of the valve open condition of adjustment or said motor, means responsive to a stop indication ior releasing said tripping means, and means for resettingsaid tripping means.

5. In an automatic control system for a prime mover, means for giving start and stop indica- V tions thereto, a governor mechanism, valve means normally adjustable by said governor mechanism for regulating the supply oi operating fluid to said prime mover during normal running operation thereof, a second valve in series with said valve means for controlling the supply or operating fluid to said prime mover, a servo-motorfor operating said second valve, means including an electric motor for controlling the valve opening operation 01 said servo-motor, tripping means,

for. causing closure of said second valve, means responsive to a stop indication for eiiecting the release of said tripping means to cause shut down of said prime mover, and means responsive to a start indication for causing said electric motor to first reset said tripping means.

6. In a control system for a prime mover, means for giving start and stop indications thereto, a valve for controlling the supply operating fluid to said prime mover during the starting and stopping operations thereoi, actuating means for opening said valve, tripping means for causing the closure of said valve, means responsive to a start indication for causing periodic energization of said operating means and progressive opening movements of said valve, means responsive to a predetermined intermediate condition or speed of said prime mover during the starting thereof for effecting release 01' said tripping means,. and means for causing the resetting of said tripping means and conditioning said control system for continuation with the automatic starting procedure.

All

said tripping means, and means for releasing said tripping means during starting operation of said prime mover for testing the operability of said tripping means and said second valve.

8. In a control system for a prime mover, means for giving start and stop indications thereto, a governor mechanism, a valve adjustable by said governor mechanism iornormally regulating the supply of operating fluid to said turbine during normal running operation thereof, a second valve for controlling the supply or operating fluid to said prime mover, actuating means for opening said valve, means responsive to a start indication for energizing said actuating means, a tripping means for causing closure of said second valve, means responsive to a predetermined abnormal condition of operation of said prime mover during the running operation thereof for releasing said tripping means,'means responsive to a stop indication on'said system for causing the release of said tripping means, and means responsive to a predetermined normal condition of operation of said prime mover during the starting thereof for releasing said tripping means.

9. In combination, an elastic fluid turbine. a valve or controlling the flow of operating fluid thereto, means for automatically adjusting said valve relatively slowly in the opening direction by increments at spaced intervals of time, means for automatically tripping said valve closed upon said turbine reaching approximately full speed, means responsive to-agpredetermined decrease in the turbine speed for readjusting said valve rapidly to an intermediate opened position, and means for automatically eflectingrelatively slow adjustment or said valve to the full open position.

10. In combination with an elastic fluid turbine having a control valve, means for automatically starting said turbine including means torautomatically adjusting said valve to a predetermined intermediate open position for causing said turbine to rotate at a predetermined intermediate speed, and means for automatically efiecting adjustment of said admission valve to a wider opened position alter a predetermined period of operation of said turbine at said intermediate speed.

11. In an electrical control systemicra prime mover, a valve for controlling the admission of operating fluid to said prime mover, means for effecting gradual opening of said valve to accelerate said prime mover to a first predetermined intermediate speed, means for enacting the tripping of said valve to the closed position upon said prime mover reaching said speed, means for efiecting thereopening of said valve relatively rapidly to a position somewhat less than said intermediate speed position, and means for effecting the gradual adjustment or said valve to a second higher predetermined prime mover speed position.

12. In an electrical control system for an elastic fluid turbine having an elastic fluid admission control valve, means for effecting the operation of said valve to a predetermined open position for admitting fluid to said turbine for heating the same without causing said turbine to rotate, means for automatically effecting adjustment of said valve to a further open position to cause rotation of saidturbine, and means.for efiecting the closure of said valve uponsaid turbine being rotated at a predetermined relatively slow speed.

13. In combination aprime mover having a valve for adjusting the supply of operating fluid thereto, an operating motor for said valve, a pilot motor for controlling said operating motor for step by step operation, an electrical controller for said pilot motor, and means including a plu rality of limit switches operatively associated with said pilot motor for stopping said pilot motor in predetermined positions of said valve.

14. In an automatic control system for a power plant comprising a prime mover and motor driven auxiliary apparatus, means for sequentially starting said auxiliary apparatus and said prime mover, and means responsive to a predetermined abnormal condition of operation of said auxiliary apparatus for precluding the starting of said prime mover by said first-mentioned I,

means.

15. In an automatic control system for a prime -mover power plant including an oil pump, means for'starting said oil pump, means including a device responsive to a predetermined oil pres-.

sure for enabling the starting of said prime mover plant, said oil pressure responsive device being eflective for immediately shutting down said prime mover either during starting or running operation thereof upon a predetermined drop in oil pressure, and means for maintaining said oil pump in operation during shutting down operation of said power plant until said prime mover is stopped.

16. An automatic control system'for a prime mover power plant including an oil pump, means for initially starting said oil pump, means for precluding the starting of said prime mover until the occurrence of a predetermined condition of operation of said oil pump, and means responsive to excessive prime mover bearing temperature for effecting shut down of said power plant independently of said last-mentioned means.

1'7. In an automatic prime mover power plant starting and stopping control system, a controller having a plurality of positions said controller in each of said position establishing cir; cuits for eflecting a predetermined series of power plant starting operations, means responsive to a completion of a predetermined series of operations for shifting said controller to a check position, and means for advancing said controller for effecting the next succeeding series of operations.

18. In an automatic prime mover power plant starting and stopping control system, a controller having a plurality of operative positions, said controller in each of said positions establishing circuits for effecting a predetermined series of power plant operations, a motor for operating said controller, means responsive to a completion of each of said series of power plant operations for energizing said motor to shift said controller to'the next successive contact making position, and signalling means automatically operable in the event that a predetermined group down position.

20. In a system for controlling a power plant of s'eriesof power plant operations is not comseries of power plant operations, a motor forshifting said controller progressively from one contact making position to the next, means responsive to a predetermined completion of each of said predetermined series of operations for energizing said motor to shift said. controller to the next successive position, and means respon-.

sive to a predetermined abnormal condition of operation of said power plant for causing the continuous energization of said motor to shift said controller directly to a power plant shutcomprising a prime mover and a generator coupled thereto, a switch for connecting said generator to a line load, means for regulating said prime mover so as to increase the line load carried by said generator, means responsive to a first predetermined abnormal condition of operation of said ,power plant for automatically effecting the gradual unloading of said generator, means responsive to the continuance of said abnormal condition of operation for effecting the disconnection of said generator from said line and subsequent shutdown. of said prime mover, and other means for maintaining the operation of said prime mover upon termination of such abnormal condition prior to the disconnecting of the generator.

21. An automatic control system for a power plantcomprising a prime mover having a generator and an exciter coupled thereto, valve means for controlling the supply of operating fluid to said prime mover, control means for said valve means for accelerating said prime mover from standstill to substantially normal running speed, means responsive to a predetermined exciter potential for eflecting the connection of said exciter to the field of. said generator, an auxiliary source of excitation, means effective upon the iailure of proper exciter potential for causing the connection of said auxiliary source of excitation to the field of said generator, means responsive to the generator potential for varying the excitation connected thereto to adjust the generator potential to a predetermined value.

22. In an automatic control system for a power plant comprising a prime mover having a generator and an exciter coupled thereto, valve means for controlling the supply of operating fluid to said prime .mover, control means for operating said valve relatively slowly for accelerprime mover for connecting said voltmeter for regulating the generator potential by varying the exciter potential. v

23. In an automatic control system for a power plant comprising a prime mover having a generator and an exciter coupled thereto, said generator being connectable to a line valve means ment of the excitation voltage, a speed governor operatively associated with said prime mover valve means, meansresponsive to a differential indication of line and generator voltages for adjusting said governor means responsive to a preenergization of said auxiliary apparatus, means responsive to a predetermined condition of operation of said auxiliary apparatus for efiecting the starting of said elastic fluid turbine, means responsive to exciter potential during an intermediate speed of said turbine for connecting said exciter to said generator, means responsive toa predetermined voltage condition of said generator for connecting said generator to a line, means responsive to a predetermined abnormal condition of operation of said power plant for effecting first agradual unloading of said generator and the disconnection thereof from said line, and subsequently theshutdown of said turbine, and means for maintaining said motor driven auxiliary apparatus energized until after the stoppingof said turbine.

25. In an automatic control system for a prime mover power plant including a prime mover, a generator and an exciter coupledto said prime mover, and motor driven auxiliary apparatus for said prime mover, manually operable means for efifecting the energization of said motor driven auxiliary apparatus, means responsive to a predetermined condition oi adjustment of said prime mover and to a predetermined condition of operation of said auxiliary apparatus for effecting the starting of said prime mover, control means for effecting the gradual acceleration of said prime mover to running speed, means for connecting said exciter to the generator field, means responsive to line and generator voltages for effecting connection of said generator to a line, manual control means for said prime mover to adjust generator load, and means responsive to an abnormal condition of operation of said power plant for effecting first an unloading of said generator and subsequently the stopping of said prime mover and ultimately the deenergization of said auxiliary apparatus.

26. In an automatic control system for a prime mover power plant including a turbine, a generator and an exciter coupled to said turbine and motor driven auxiliary apparatus for said turbine, manually operable means for conditioning said system to eflect the energization of said motor driven auxiliaryapparatus, a first valve for controlling the supply of-operating fluid to said turbine during normal turbine running operation, a second valve for controlling the supply of operating fluid during the turbine starting and stopping operations, means responsive to a predetermined condition of operation of said auxiliary apparatus and condition of adjustment of said valves for effecting the opening of said second valve by increments at spaced intervals of time, means responsive to exciter potential for effecting connection of the exciter to the generator field during an intermediate turbine speed condition, a governor responsive to normal turbine running speed for operating said first valve as said second valve is moved to a wide open position, means for connecting said generator to a line, and manually operable means for adjusting said governor so as to regulate generator load.

27. In an automatic control system for a prime mover power plant including an elastic fluid turbine, a generator and an exciter coupled to said turbine and motor driven auxiliary apparatus, a controller having a plurality of positions for effecting a predetermined series of power plants starting and stopping operations, a motor for driving said controller, manual control means for said controller motor for efl'ecting movement thereof to a first position, and means responsive to movement of said controller to said first position for efi'ecting energization of said motor driven auxiliary apparatus, means responsive to a predetermined condition of operation of said auxiliary apparatus for permitting the energization of said controller motor for movement thereof to a second controller position, an elastic fluid admission controlling valve for said turbine and operating means therefor responsive to said controller in the second position thereof for effecting the starting of said turbine and bringing said turbine to substantially normal running speed in a plurality of steps, means for connecting said exciter to the generator field during an intermediate speed condition of said turbine, means for connecting'said generator to a line load, means responsive to a predetermined abnormal condi-' tion of operation of said power plant for effecting 'movement of said controller to a further position for automatically efiecting first the unloading of said generator and the disconnection thereof from said line load and subsequently a complete shutdown of said prime mover power plant.

- 28. In an automatic control system for a prime mover power plant including an elastic fluid turbine, a generator and an exciter coupled to said 7 turbine and a motor driven auxiliary apparatus for said turbine, manually operable means for conditioning said system to effect the energization of said motor driven auxiliary apparatus, a first valve for controlling the supply of operating fluid to said turbine, means for automatically adjusting said valve slowly in the opening direction for accelerating said turbine from standstill to its normal running speed, a second valve for regulating the supply of operating fluid to said turbine, a turbine speed governor for adiusting said second valve during normal running operation of said turbine, means for holding said second valve in a predetermined partly closed position during starting, means for actuating said holding means so as to allow movement of said second valve i n the opening direction after said turbine reaches normal running speed, means responsive to a predetermined abnormal condition of operation of said power plant during starting of said turbine for eiiecting movement of said 

